Turbine engine blade made of composite material, and a method of fabricating it

Abstract

A turbine engine blade made of composite material including fiber reinforcement densified by a matrix is fabricated by a method including: performing three-dimensional weaving to make a single-piece fiber blank; shaping the fiber blank to obtain a single-piece fiber preform having a first portion forming a preform for a blade root and an airfoil, at least one second portion forming a preform for a blade inner platform or for wipers of a blade outer platform, and at least one third portion forming a preform for reinforcing a blade inner platform or for overhangs of a blade outer platform; and densifying the fiber preform with a matrix to obtain a composite material blade having fiber reinforcement constituted by the preform and densified by the matrix, and forming a single piece with an inner and / or outer platform incorporated therein.

Description

BACKGROUND OF THE INVENTION[0001]The invention relates to turbine engine blades made of composite material comprising fiber reinforcement densified by a matrix.[0002]The intended field is that of gas turbine blades for aeroengines or industrial turbines.[0003]Proposals have already been made to fabricate composite material blades for turbine engines. Reference may be made in particular to patent applications FR 2 939 129 and FR 2 939 130 filed jointly by Snecma and Snecma Propulsion Solide. Those applications describe in particular fabricating a turbine engine blade out of composite material comprising fiber reinforcement densified by a matrix. More precisely, the method described in those two documents and applied to fabricating a blade presents the special feature of a fiber blank that is made by three-dimensional weaving and that is shaped in order to obtain a single-piece fiber preform with a first portion forming a preform for a blade root and an airfoil, and at least one secon...

AI Technical Summary

Benefits of technology

[0005]A main object of the present invention is thus to mitigate such drawbacks by proposing a blade of composite material that forms a single piece having an inner and / or an outer platform incorporated therein, and in which the outer and inner platforms present the required properties.

[0010]Compared with the method described in patent application FR 2 939 129 and in patent application FR 2 939 130 in its application to fabricating a blade, the invention applies in particular to making use of a third portion while shaping the fiber blank, which third portion forms a preform for reinforcement of a blade inner platform or for overhangs of a blade outer platform. As a result, the blade obtained by the method of the invention may present the required properties, i.e. a sealing function and an aerodynamic function at its outer platform and an inner platform having twice the thickness, thereby reinforcing its mechanical strength.

[0013]Providing non-linked zones enables the fiber preform to be shaped without cutting linking yarns, where such cutting can reduce the mechanical strength of the fiber reinforcement and thus of the blade that is fabricated therefrom.

[0014]According to another feature of the method, the fiber blank is woven with second and third continuous sets of yarn layers and the shaping of the fiber blank includes eliminating portions of the second and third sets of yarn layers that lie outside the or each second fiber blank portion and the or each third fiber blank portion by cutting them off.

Problems solved by technology

The blade obtained by such a method presents the drawback that its outer platform cannot incorporate both a function of providing sealing with the casing that surrounds the blades (by having wipers present) and an aerodynamic function (by having overhangs present that define the outside of the flow passage for the gas stream through the turbine).

Furthermore, at its root, the overhangs of the inner blade platform that is obtained by that method can break under the effect of the high levels of force to which they are subjected in operation (this force being due to the centrifugal force of rotation).

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